I am trying to identify the cause of a rough idle and lots of idle smoke from my B4 Passat TDI. On cold start, the car is very rough as if it dropped a cylinder. MB 13 says injector 1 is 0.0, injectors 2 and 3 are 2.99 and for some reason injector 4 is blank. After a couple minutes the car idles a little better, still smokes and injector 1 toggles between .02 and 1.04. What exactly are these numbers measuring? Does this indicate injector 1 is not open most of the time and working intermittantly and why a blank field for injector 4? THANK YOU.